Case of the Month - November 2011
Dr Andrew Whitelaw, Principal Specialist, National Health
Laboratory Service
An 86 year old male patient was admitted to an orthopedic ward
with a right hip fracture and a right sided pleural effusion.
Co-morbidity included diabetes mellitus and hypertension and he
was in chronic renal failure on hemodialysis. The patient
underwent open reduction and internal fixation of the right hip
and had a right sided thoracostomy for the pleural effusion and
was subsequently admitted to a high care unit (HCU). Two weeks
later the patient was discharged to a renal ward for ongoing
hemodialysis. A few days later the patient became delirious with
fever and had an increased C-reactive protein and white cell
count. Blood cultures and urine cultures taken at the same time
revealed no growth. Ten days later whilst on empiric meropenem
and linezolid he became hypotensive and obtunded; one day later
a urine MC&S grew a Klebsiella pneumoniae that, according to
automated susceptibility testing (Vitek 2), was resistant to all
commonly used antibiotics (i.e. amino-penicillin’s, β-lactam/β-lactamase
inhibitors, aminoglycosides, fluoroquinolones, cephalosporins,
tigecycline and carbapenems). Subsequent disc susceptibility
testing, showed that fosfomycin and colistin were the only
active agents. Based on MIC testing, colistin was the only agent
active against this pathogen. The isolate was genotypically
analyzed by the Ampath molecular laboratory in Pretoria, to
detect the presence of carbapenemase genes and sequencing
confirmed the presence of the NDM (blaNDM-1 ) gene. The patient
demised however without having received colistin and prior to
all the tests being completed.
During his prolonged hospitalization of 40 days the patient
received multiple courses of antibiotics which included:
- Ciprofloxacin
- Vancomycin
- Metronidazole (for PCR- confirmed Clostridium difficile
diarrhea)
- Meropenem
- Linezolid
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